Grey matter is primarily made up of the neurons themselves, while white matter comprises the material that connects neurons and bridges in different parts of the brain.

For the study, published in Current Developments in Nutrition, the team gave pregnant sows choline-deficient or choline-sufficient diets through the second half of their pregnancies.

After weaning, piglets were fed choline-deficient or choline-sufficient milk replacer for 30 days. Then the month-old piglets were scanned by magnetic resonance imaging (MRI).

The left and right cortex were found to be larger in the choline-sufficient pigs, as a result of the a greater density of grey matter in the brain.

Consumption of choline - an essential nutrient found in liver, eggs, wheat germ - during pregnancy may improve metabolism and brain development of babies, say researchers. Picture: Pexels

As part of the study, some of the pigs from choline-deficient mothers were also given adequate amounts of choline after birth.

The results showed that it is not sufficient for the brain.

"Postnatal supplementation cannot correct for prenatal deficiency. It has to occur during development," explained Ryan Dilger, associate professor at the varsity.

"We know that the structural alteration is there, but it may not manifest in ways we can see until later in life. That's why it's important to think about this during gestation because the changes are occurring then," Mudd noted.